Wumeiliren mining machine

1. I played Kwai for more than a year, and I won't laugh after watching this video.

2. Maybe the number of students has increased and the tuition has also increased. But it felt like the atmosphere was good. Because it is small class teaching, there are not many people. The teacher is very friendly and responsible. If you live nearby, it is recommended to be a fitness center. I usually choose 6.20-7.20 PM. I can't help it. I have to go home and take care of the children. Dancing, I think it's a good way to lose weight and shape. I like belly dancing& lt;...

3. 10 yuan ticket for black dance hall 10 yuan for a dance

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5. I think he's wrong. Because as far as I know and the information I have consulted, it is not mentioned that the muffler (suppressor) has the function of flame suppression. I don't think it's possible to judge whether a muffler (suppressor) is used simply because there is no burn. It can be seen from a lot of data that even if a muffler is installed, there is still flame from the muzzle of the gun. The original text should be flame eliminator?? If there is no burn, it should be long-range shooting, I think. Or there is a possibility that this is a kind of muffler that works like a tube that uses an object to block the propellant gas and make it release slowly. But I don't know how the man judged

6. The principle of automobile muffler is to use the appropriate combination of cavity and pipe to achieve two kinds of effects: one is to use the sudden change of pipe section (that is, the change of acoustic reactance) to make the sound wave propagating along the pipe reflect back to the sound source direction, so that the sound energy can be reflected back to the original place; the other is to use the change of pipe section (that is, the change of acoustic reactance) to make the sound energy reflect back to the original place; The second method of automobile muffler is to use the reflection of several interfaces to make the first forward propagating sound wave return to the original point, and then return to the forward propagating point again. This point is combined with the second forward propagating sound wave which has not been reflected, and the two waves are equal in amplitude, and the difference in phase is an odd multiple of 180 degrees, so as to interfere with each other and offset each other. The principle of automobile muffler is introced in "interference of wave" in Chapter 9 "mechanical wave" of high school physics: the exhaust pipe is composed of two pipes of different length, which are separated first and then intersected. Because the length difference of the two pipes is equal to half of the wavelength of the sound wave emitted by the car, the interference of the two lines of sound waves will cancel each other and weaken the sound intensity, so that the sound will be reced, so as to achieve the effect of silencing. According to its working principle, automobile muffler can be divided into resistance muffler, Resistance Muffler and impedance compound muffler. The Resistance Muffler mainly uses sound-absorbing materials to rece noise. The sound-absorbing materials are fixed on the inner wall of the air flow pipe or arranged in the pipe in a certain way. When the sound wave enters the muffler, most of the sound energy is absorbed and plays a role in noise elimination. The advantage of the Resistance Muffler is that it can eliminate noise in a wide range of medium and high frequency, especially for high-frequency sound waves. The disadvantage of automobile muffler is that it has a short service life in high temperature steam and corrosive gas. Automobile muffler is also called acoustic filter, which can be divided into resonance type, expansion chamber type and interference type. The simplest expansion chamber type automobile muffler is connected with a large section of thick pipe on the air passage pipe, but its end is a thin pipe. The section buckle length of the expansion chamber (large pipe) is adjusted to change the reflection and interference performance of sound waves, so as to change the amount of noise elimination and the maximum frequency of noise elimination. It is different from the resistive automobile muffler in that there is no sound absorption material in it. The advantages of the resistant automobile muffler are simple structure, high temperature resistance, gas corrosion resistance and good low-frequency noise elimination performance. The disadvantage of the resistant automobile muffler is narrow noise elimination frequency band. It is mainly used for the intake and exhaust ports of automobile engine and other piston engines. The impedance composite muffler is made by combining the first two advantages. There are not only resistive sound-absorbing materials, but also resistant filtering elements such as resonant cavity and expansion chamber in it, so it has good noise elimination effect in a wide frequency range. Engine noise mainly includes combustion noise, mechanical noise, intake and exhaust noise, cooling fan and other components. To rece combustion noise, it is necessary to improve combustion conditions and combustion quality to achieve smooth pressure waveform. The most effective combustion can be achieved by reasonable arrangement of spark plug, spark plug and valve, proper combustion chamber type and cooling mode. In terms of fuel, the higher the octane number of gasoline, the better the ignition quality and antiknock performance. Mechanical noise, in the case of ensuring that the engine output power does not decrease, the intake and exhaust noise can be reced by improving the engine valve mechanism or exhaust mechanism. At present, the widely used paper air filter and exhaust muffler can significantly rece the intake and exhaust noise At present, the main solutions to the vibration and noise are as follows: 1. It is mainly used at the vibration source to rece the amplitude of vibration wave; ② Vibration isolation treatment. In order to rece the vibration source, the vibration isolator is installed in the way of vibration wave transmission; ③ Damping treatment. Most of modern structures are complex multi degree of freedom systems, and most of them are broadband excitation. Increasing damping can effectively suppress vibration. The common methods to deal with this problem are the damped free layer and the constrained layer. In order to rece the noise of high-speed engine fan, the fan with hydraulic coupling or variable torque angle can be used, and the water temperature inction electric clutch fan can also be used. When the fan material is changed to nylon, the fan noise can be reced to a certain extent. To solve the noise of vehicle engine is a technical problem involving all aspects of the whole machine, including the structure, material, mass distribution, process level, assembly sealing and so on. Manufacturers take active measures to prevent and control noise in the structure of vehicle engine, including: adopting vibration absorption and sound insulation technology, improving vehicle structure, setting sound insulation board and muffler within a certain distance from the sound source, adopting rear suspension engine for passenger cars, improving vehicle muffler structure, etc.

7. It is too laggy to see the sail.

9. Yes, I do not know from which day, the search engine suddenly turned into a cloud sail. But I can make do with it. Select "more webcast" to get a list of videos in the webcast format.

10. The next old version of the webcast, after loading, immediately delete the upgrade program, or directly download the 3.5 version without upgrade